A) Related Applications
This application is related to an application of Charles D. Stormon, Abhijeet Chavan, Nikos B. Troullinos and Raymond M. Leong which is filed concurrently herewith, Ser. No. 08/284/347, filed Aug. 1, 1994, and which is entitled "A Content Addressable Memory Array Integrated with a General Logic Block".
B) Field of the Invention
The present invention relates to the field of data processing incorporating a content addressable memory, associative storage, parallel-search storage or the like wherein high performance of data searching, processing of stored data or processing of search results is required.
C) Art Background
In a conventional computer, processing of the contents of a memory is carried out in a single instruction single data (SISD) fashion. A single word in a memory is selected for access by an address that uniquely identifies that word. Instruction sets for the prior art have been based on selecting single operands by unique addresses with no provision for accessing multiple stored words for concurrent operations.
Content addressable memories (CAMS) are used generally in associative memory processing and specifically in computer data processing wherein it is desirable to identify the location of the data stored in the memory by specifying part or all of its contents. However, CAMs have not been popular because of high manufacturing cost and low performance of data searching and data processing.
The present invention significantly increases the performance of applications that include searching stored data and/or processing the stored data or search results. This class of problems is typically handled in prior art by software algorithms that search and process data in a serial (or a SISD) fashion. CAM array 10 in FIG. 1 of the present invention supports a concurrent search that compares all of the stored CAM words to the input data in one operation, thus implemented as a single instruction multiple data (SIMD) operation. The data stored in CAM array 10 can also be processed in an SIMD fashion in accordance with the present invention. Furthermore, the present invention supports more complex operations such as finding inexact (fuzzy) matches for data that falls into a specified range.